The present invention relates to compositions and methods for reclaiming used motor oils for further use.
As a part of the regular maintenance typically required for internal combustion engines, such as automobiles, trucks, trains, airplanes, etc., the oil used for lubrication becomes contaminated and must be removed on a regular basis. After removal, the oil chamber is typically refilled with new oil. The reason that the used oil must be replaced is because lubrication oil used in-internal combustion engines readily become laced with contaminants including water, light hydrocarbons, oil oxidation products, suspended particulates, and other extraneous substances. These contamination components render the oils unsuitable for continued use. Though the used oil becomes contaminated as described, the oil itself is not consumed in the engine during the combustion process. As such, used oil or waste oil has recently been viewed as a valuable resource for reuse, assuming it could be reclaimed in a simple and efficient manner.
The particulates that end up in used lubrication oil usually consist of aggregates of carbonaceous material and compounds of lead produced in the combustion of leaded gasoline or other petroleum based fuels, as well as small quantities of metals resulting from the wear of pistons, cylinders, valves and other moving parts within the engine. In many cases, these particulates are small in size and are kept in suspension by dispersant compounds deliberately added for that purpose to fresh lubricating oil. Typically, the contaminants, depending upon the amount of use the oil has been exposed to, can comprise up to about 25% of the used oil volume.
Once the used oil has been drained from the engine, it may be disposed of by incineration, land fill deposit, or by other known disposal methods. Additionally, used oil is sometimes used in road oiling for dust control. With respect to used oil disposal, there are several reasons why such methods are undesirable. For example, used oil is a hazardous waste that can have an adverse effect on the environment. Even if it is incinerated or burned, it may put toxic materials into the air. Additionally, if used motor oil is not properly handled with respect to land fills, it can contaminate soil and eventually groundwater. Because of these and other environmental concerns, waste oil is sometimes stored in barrels or other containers, but this is a very expensive alternative. As these alternatives have both environmental and financial drawbacks, many have attempted and, to a limited extent, succeeded in developing approaches to re-refine used motor oil.
In many of the re-refining systems of the prior art, water and sediments are removed by the use of chemical emulsion breakers. Next, the acidic compounds in the oil are neutralized and then treated with additional caustics and acids to assist in the removing of the carbonaceous compounds created during the combustion process. The oil is then introduced into a distillation column for treatment with hydrogen to clarify and purify this material for use once again as a lubricating oil. Though this method is effective in treating used motor oil, the operating costs are relatively expensive and the initial investment to start such a facility are often prohibitively expensive.
In addition to the basic approach described above, many variations on this and other known approaches exist including solvent treatment, acid and alkali washing, and high-temperature distillation. For example, in U.S. Pat. No. 3,763,036, methyl ethyl ketone (MEK) has been shown to result in slow flocculation of particulates which may then be removed by gravity settling or by centrifugal separation. Additionally, in U.S. Pat. No. 3,639,229, a process is described where a mixture of an aliphatic monohydric alcohol of from four to five carbon atoms and a light hydrocarbon are added to waste oil. Once the mixture settles into three distinct layers, the upper oily layer is recovered, treated with sulfuric acid and thereafter refined by conventional methods. Additionally, in U.S. Pat. No. 3,919,076, a process is described that involves removing water and adding a saturated hydrocarbon solvent to the waste oil, settling the mixture to recover the oil/solvent mix, removing the solvent from the mixture, vacuum distilling the residual oil to collect selected fractions, hydrogenating the fractions in the presence of a catalyst, stripping hydrogenated oil to remove light ends, and filtering the remaining products. U.S. Pat. No. 4,124,492 discloses a process for reclaiming useful hydrocarbon oil from contaminated waste oil. In that process, the waste oil is dehydrated and then dissolved in selected amounts of isopropanol. The undissolved waste matter is separated and the residual oil/solvent fraction is distilled to recover the decontaminated oil and solvent. A bleaching clay or activated carbon at elevated temperatures is then used to further process the oil.
Though some of these methods of reclaiming used oil have proven to be useful in their own right, it would be useful to provide an alternative method of reclaiming used motor oil that is simple, effective, and economical to practice.
A composition and method of reclaiming used motor oil for further use is disclosed comprising admixing used impurity laden motor oil with an effective amount of acetone as a flocculating agent and an effective amount of a second ketone as a wetting agent, thereby forming an oil impurity flocculent mixture. The mixture is then subjected to a force such that a heavy phase and a light phase are formed. The light phase is comprised of lean or purified motor oil, acetone, and a second ketone. The heavy phase is comprised of flocculated impurities (at least some of which can be resuspended as part of the heavy phase), any remaining acetone, and any remaining second ketone. The light phase containing the lean motor oil is then separated from the heavy phase containing the flocculated impurities. The lean oil can then be separated from the acetone and the second ketone, usually by a vapor recovery process.